ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic stress responses.
Genotoxic stress triggers the activation of checkpoints that delay cell-cycle progression to allow for DNA repair. Studies in fission yeast implicate members of the Rad family of checkpoint proteins, which includes Rad17, Rad1, Rad9 and Hus1, as key early-response elements during the activation of both the DNA damage and replication ... checkpoints. Here we demonstrate a direct regulatory linkage between the human Rad17 homologue (hRad17) and the checkpoint kinases, ATM and ATR. Treatment of human cells with genotoxic agents induced ATM/ATR-dependent phosphorylation of hRad17 at Ser 635 and Ser 645. Overexpression of a hRad17 mutant (hRad17AA) bearing Ala substitutions at both phosphorylation sites abrogated the DNA-damage-induced G2 checkpoint, and sensitized human fibroblasts to genotoxic stress. In contrast to wild-type hRad17, the hRad17AA mutant showed no ionizing-radiation-inducible association with hRad1, a component of the hRad1-hRad9-hHus1 checkpoint complex. These findings demonstrate that ATR/ATM-dependent phosphorylation of hRad17 is a critical early event during checkpoint signalling in DNA-damaged cells.
Mesh Terms:
Animals, Cell Cycle, Cell Cycle Proteins, Cell Line, DNA Damage, DNA-Binding Proteins, Doxycycline, Humans, Mice, Mutagens, Phosphorylation, Protein-Serine-Threonine Kinases, Serine, Tumor Cells, Cultured, Tumor Suppressor Proteins
Animals, Cell Cycle, Cell Cycle Proteins, Cell Line, DNA Damage, DNA-Binding Proteins, Doxycycline, Humans, Mice, Mutagens, Phosphorylation, Protein-Serine-Threonine Kinases, Serine, Tumor Cells, Cultured, Tumor Suppressor Proteins
Nature
Date: Jun. 21, 2001
PubMed ID: 11418864
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